Just days after he was sacked as the White House director of communications, Anthony Scaramucci received an email from a fellow Donald Trump White House exile, Reince Priebus. It was a combative message, which triggered an equally angry response from “the Mooch”, in which he suggested Priebus “read Shakespeare. Particularly Othello”.

The problem? The person Scaramucci was communicating with wasn’t Priebus. It was a British man with a smartphone. That same person has pranked Trump’s right hand man, Steve Bannon, as well as the heads of the Bank of England and Barclays. For his latest coup, published earlier this week, SINON_REBORN hoodwinked Jared Kushner’s lawyer into a conversation, thinking he was talking to the US president’s son-in-law. When the emails were posted on the prankster’s Twitter account, Abbe Lowell joined a long list of victims. SINON_REBORN had struck again.

The prankster’s road to the inner workings of the White House started three years ago, in the offices of a large advertising agency in Manchester. “I remember noticing one day that when you got an email, the email address didn’t show by default,” he says. “You had a display name, and you could put any name you wanted in there.”

The 39-year-old web designer, whose real name is James Linton, decided to test the email setup. He sent a message to a close work colleague, taking on the persona of the CEO and using an account with the right display name. The email asked the colleague to attend a meeting about an allegation of sexual harassment. The problem? Linton couldn’t keep a straight face. When his colleague read the email and looked over to him, his laughter gave away the game.

But now Linton had the taste for email pranks. Using the same address, he messaged a colleague as the company CEO saying he’d been selected to represent the company at an international competition held in Israel. “He completely fell for it,” Linton says. But things almost went awry: the colleague then went up to the real CEO to shake his hand and thank him for selecting him. “My heart was in my mouth,” recalls Linton.

The emails remained office jokes until Linton asked for a £500 loan at a branch of Barclays. At the time, he says, had a gambling problem (for which he has since gone through rehab) and mental health issues. The request was declined when the bank looked through his statements – and the vast outflows of money to gambling sites – but he was given four consecutive loans worth £15,000 through the bank’s app. He felt annoyed that he’d been allowed to get into problem debt, and Barclays’ response wasn’t sufficiently helpful. “That’s what made me feel I needed to get my own back.”

So he found the email address of the Barclays CEO, Jes Staley, and sent him an email purportedly from John McFarlane, the bank’s chairman. The email address he used for his con? john.mcfarlane.barclays@gmail.com. Staley sent back effusive praise for the person he thought was McFarlane; the prankster leaked it to the press, causing embarrassment to the CEO, and resulting in Barclays refiguring their email systems to notify users when they send emails to non-company addresses. SINON_REBORN – a name he borrowed from the man who convinced the people of Troy to take in the Trojan horse as a way of “sound[ing] more intelligent than I really am” – had arrived on the scene.

From there, SINON_REBORN had what he calls the “tricky second album dilemma”: finding a high-enough profile target that could match his first public foray into email pranking. He hit on the Bank of England.

He logged onto their website, picked out the name of Anthony Habgood, a high-ranking board member, and sent out an email in his name to Mark Carney, the Bank’s governor. Carney fell into the trap, making ill-judged remarks about one of his predecessor’s penchant for booze, before realising he’d been conned and clamming up.

This is how SINON_REBORN works. First, he’ll decide on a target, quickly Google their personal and professional connections to try and figure out who would be best to impersonate, then fires off an email to them. Usually it’ll be a line or two, asking for a comment on a recent news story. “Short things like that seem to work the best,” he says – and being sparse when using punctuation helps convince people of an email’s veracity (as does adding “Sent from my iPhone” to the end of messages. “When you see that, you think someone is walking about, on their phone, getting on an escalator,” he says. “It doesn’t conjure up the image of somebody huddled over a laptop in their hoodie.

“In many ways it’s similar to the high of gambling,” Linton says. “You fire out three emails, and one of them comes up. When it does, you realise you have one on the line. There’s excitement.”

The email prankster’s first few targets were designed to poke fun at the establishment – but his next big hoax went too far, he feels. Posing as Seumas Milne, the Labour Party’s press chief, he managed to coax out of Diane Abbott that she suffered from diabetes. (The prankster fooled Abbott by pretending to be Jeremy Corbyn and emailing her parliamentary assistant, supposedly in error. The assistant then directly connected Linton to the MP.)

“That felt a bit weird to me, that this private information had come out, but people lapped it up,” he says. “Looking back now, it probably was a step too far; I would’ve blanked that bit out.” It also strayed from the initial quirky, oddball humour that Linton tried to imbue his pranks with – in part because he felt it might provide a buffer against legal action.

“It’s not really a legal grey area,” he says. “It’s quite black and white: it’s fairly illegal, what I do. That’s why I stick so much humour in there: ideally, they wouldn’t want all that to be revealed in the more formal surroundings of a court.”

He’s aware that he’s butting up against the fringes of acceptability, but also knows that what he does has struck a chord. “A lot of people seem to really relate to it, especially in America at the moment,” he says. “The little man is getting a chance to cause a bit of mischief, I guess.”

Targeting political victims has in turn caused JamLintones to change the way he picks people to prank. “There’s been a metamorphosis,” he says. “I read stories where I get genuinely angry, and that often leads me to say: ‘Well, maybe you’ll be next on the list.’”

He draws the line at pranking some people, though. “That kind of happened with Kevin Spacey,” he explains. Mid-prank, while in the role of Hugh Jackman and asking the House of Cards star for his thoughts on a potential Wolverine musical, Linton suddenly felt in awe of Spacey, and decided to pull the plug.

Others, though, he cares less for. Take his latest prank: a conversation with Abbe Lowell, Jared Kushner’s lawyer, which was released on September 26th, about the latter’s use of a private email account for official White House business, yet another prod at the Trump White House. However, when we speak – hours before the prank is published by Business Insider – Linton has already moved on, forgetting the name of his victim. “That’s how deep I go into it,” he jokes; “I don’t even remember their names.”

The prankster has bounced between Patreon, Paypal and GoFundMe – which cancelled his fundraising campaign and refunded the £400 people had pledged – for funding, as well as making money from Britain’s tabloid newspapers for feeding them embarrassing email exchanges. But he knows it’s a long-term career. “I’d love to do it in a year’s time, but I can’t see how it’ll have enough legs to keep going,” he says.

“I’m not after paycheques for life,” Linton explains. “I’m just after a roof over my head for the next few months while I decide what to do with the rest of my life.”

Not that he’d ever fully be able to step away from the pranking persona, even if he found a new career. “I’m sure even if I gave it up, I’d be coming back to pranking five years from now,” he says. The highs, when they come, are too powerful for this reformed gambler.